A "drop" in a manhole is constructed as a piped drop (say greater than 2 foot as bimr says) - your local authority will have standard drawings of how to construct the drop pipe - it will have a "gun-bend" at the bend down - allows access for sewer cleaning. The drop pipe is usually a size...
All good advice
Another warning is if your well depth is significant compared to static lift component of discharge head then just drawing the well down will reduce the discharge rate - depends on operating range of start/stop in station
And as others advised need to calibrate one pump, then...
A rule of thumb in orifice distributor systems is to make the head loss through each office say 10 times the head loss along the length of the header - and if it is wastewater - put a filter on feed side that will trap particles that would block your orifices (sorry about that) . So if the head...
I agree with others - it is important to stabilise the stripped surfaces first - these are probably dispersive soils - these can be covered with non-dispersive material if possible, or ripped and have lime or gypsum placed in , mixed an compacted - but if it keeps raining you will make a mud...
The backwash flow rates sound very low to me for say a sand filter or even a multi-media filter with some filter coal as second layer - have you converted these from other units? If the manganese filter is a green sand filter or some "rare earth" media or very low SG media - that may explain it...
You will need to find out where your water supply comes from too - is it from "your" site such as a river, dam, well or bore or rainwater tank? - and are you legally entitled to the water?
Or is it from the local Council or water authority pipe out in the street?.
If it is from Council/Water...
Algae in FRP Tanks - I have seen this in a roofed FRP storage tank after MF, ozone GAC; client very unimpressed - this was definitely due to diffuse light penetration - algae require light. Of course be sure to get any micro-biolgical (or other) slime/scum/growth analysed to confirm your...
